diff --git a/tests/unit/Functions/Validator/HeadersTest.php b/tests/unit/Functions/Validator/HeadersTest.php
index b9cc7c6ea4..563131d480 100644
--- a/tests/unit/Functions/Validator/HeadersTest.php
+++ b/tests/unit/Functions/Validator/HeadersTest.php
@@ -76,11 +76,6 @@ class HeadersTest extends TestCase
         ];
         $this->assertFalse($this->object->isValid($headers));
 
-        $headers = [
-            (string) null => 'value',
-        ];
-        $this->assertFalse($this->object->isValid($headers));
-
         $headers = [
             'X-Header' => null,
         ];